you serious you just stated it's obvious from your post you are familiar with their needs it was not your post you gave no opion on the post in question you just made comment on my comment wow it appears you are very educated NOT and in your case it seems it's not mandatory to have a long neck to be a goose
if you care to read the post they are moving to Thailand and have 2 places in mind chiang mai or koh samui and out of those 2 it's samui for me and it's not about endless capital it's about managing what funds you have at your disposal 6 months of the year I choose to live in phuket is where I reside doesn't matter where you decide to live if you try and live above your means you are doomed for failure I live comfortable without the expense and it's obvious they have sufficient funds to live in samui otherwise it wouldn't be one choice of theirs
It's a no brainer with a young family koh samui is the choice if your health is important to you chiang mai has burning season every year and it's not pleasant chohk di
Ok jomtien/chonburi immigration you will require current tm30 for extension just completed mine there that is a sticking point for them basically mandatory at that office
I don't believe there is any long term visa available to you as you are a German passport holder residing in Australia for travel and work purposes not even sure with your nationality status allows you to apply within Australia
60 day tourist visa for Thailand even if you can sometimes the thai authorities take a dim view with tourist attempting to stay long term on tourist visas and you maybe questioned about your number of entries don't be surprised if you are denied entry at some point entry to Thailand is never a guarantee it's all dependent on the IO infront of you at time of entry Chokh di